OBJECT:
Estimate the moisture content, moisture regain of
textile materials by oven dry method. Calculate the correct invoice weight
(CIW).
INSTRUMENT/TOOLS:
Oven for drying, weighing balance etc.
WORKING PRINCIPLE:
The amount of moisture in sample of material may
be expressed in terms of moisture regain and moisture content. The basic method
is to weighing the sample in its original condition to dry it and then again
weight it. The oven dry weight is defined as the constant weight obtained by
drying the sample at a temperature of 105 ± 2˚C.
Moisture regain – defined as the weight of water in material expressed
as a percentage of oven dry weight.
Moisture content – defined as the weight of water in a textile
material as the percentage of the weight of material.
PROCEDURE:
•
Weigh the
given sample on electronic balance.
•
Dry the
sample in oven for 30 min at 105 ± 2˚C.
•
Now takeout
the sample in weighing bottle from oven and let it cool down with closed lid.
•
Weigh the
sample again with weighing bottle on balance.
•
Again dry
the sample in oven for 15 min at 105 ± 2˚C.
•
Repeat Till
constant dry weights are obtained
•
Calculate
the moisture regain and moisture content with help of sample weight.
FORMULA:
For correct invoice weight (C.I.W.)
Let,
C = the
oven dry weight of the consignment.
S = the
original weight of the sample.
d = the
oven dry weight of the sample.
W = the
weight of the consignment at the time of sampling.
Now,
For samples
dried out without cleaning,
Correct invoice weight = C x (100+R1)
100
Where R1is
the official allowance for moisture regain.
Total
weight of consignment =200 kg.
RESULT:
MOISTURE CONTENT…………………………………………….
MOISTURE REGAIN ………………………………………………….
CORRECT INVOICE
WEIGHT ……………………………..
PRECAUTIONS:
•
Weight
should be taken carefully after cooling the sample in bottle.
•
Time should
be noted while repeating the method.
Bottle
should be dried for 10 min in oven.
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